Charging storage batteries.



P. KENNEDY.

CHARGING STORAGE BATTERIES. 'APILIOATIOF run In. 17, 1908.

' Patented Mar.5,1912.

4 SHEETS-SHEET 1.

P. KENNEDY.

CHARGING STORAGE BATTERIES. APPLICATION FILED MA 1', 1908.

1,01 9,482. Patented Mar. 5, 1912.

4 SHEETS-SHEET 2.

' myegron ATTO F. KENNEDY. I CHARGING STORAGE BATTERIES. APPLICATIONFILED MAR. 17, 1908.

1 ,019,482, Patented. Mar.5 ,1912.

4 SHEETS-SHEET 3.

P. KENNEDY. CHARGING STORAGE BATTERIES.

APPLIGATION FILED MAR. 17, 1908.

Patented Mar. 5, 1912.

4 SHEETS-SHEET 4.

- l"lllll I PLTRICK KENNEDY, Q1 BROOKLYN, NEW YORK.

cmnemo STORAGE, BATTERIES.

' Specification of Letters Patent I Patented Mal. 5, 1912.

190a. s m No. 421,882.

\To all whom it may concern:

Be it known that I, PATRICK KENNEDY, a citizen of the United States,re'sidin at Brooklyn, in the county of Kings and tate 5 of New York,have invented'certain new and useful Improvements in Charging StorageBatteries; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

The invention relates primarily to an improved method of chargingstorage batteries so as to insure that the battery shall beantomatically recharged to its full capacity, or preferably slightlyover-charged, and yet which shall prevent an excessive overcharge.

The invention is of peculiar value in connection with train-lightingsystems in which the storage battery is charged from a generator drivenfrom the axle of the movingvehicle, so that the generator is constantlydriven when the vehicle is in motion and is not driven when the vehicleis at rest.

In railway car lighting, various means have been proposed to prevent anovercharge of the storage battery. 'These systems which have been mostwidely used in practice are (a) the system in which the generator isregulated to produce an electromotive force of constant value, so thatthe battery is charged at constant potential, and as the electro-motiveforce of the battery rises it opposes that of the generator, therebypreventing an over-charge; (b) the system in which there is insertedbetween the generator and the battery a circuit breaker which isoperated to cut ofi the charging current whenever the otential acrossthe battery. terminals reaches a predetermined maximum. These systems,which embody regulation by potential at the battery terminals, areobjectionable for the reason thatr thispotential is subject to Widevariation from causes which are independent of the actual amount ofcharge stored in the battery. The potential which must be supplied atthe battery terminals by the generator is equal to the electromotiveforce of the battery plus its internal resistance drop which is equal tothe internal resistance of the battery multiplied 1 by the currentflowing through it. If then a battery is being charged from a constantvoltage supply, as,

Application filed larch 17,

it does an increase of the electro-motive force to maintain a constantvalue of charging current, will open the potential-controlledcircuit-breaker and cut 011' the charging current before the battery hasreceived the full. charge. The internal resistance of storage batteriesis, however, subject to. wide variations due to variations intemperature;

in the quantity and density of the electro lyte; in the condition ofplates and connections, etc., and consequently such systems of chargeare quite unreliable.

Although the theoretical disadvantages of over-charging a storagebattery are perhaps frequently exaggerated, yet it is a fact that,

as a practical matter, there are certain marked disadvantages in such anovercharge, particularly in train-lighting systems. Among thesedisadvantages may be mentioned the useless expenditure of en-- ergy, andthe rapid decomposition of the water in the-electrolyte, whichif notproperly compensated for will allow a portion of the plates to becomedry, with the result that .the parts of the'negativeplates which areexposed to the air are destroyed, and the specific gravity of theelectrolyte rapidly 1ncreases, both 0f these efi'ects necessitatingfrequent inspection and correction in order to maintain normalconditions. Furthermore the long-continued over-charge may increase theprocess of formation especially in a Plant element, and therebymaterially shorten the life of the elements. It is, therefore, highlydesirable, as a practical thing, that some means should be provided forpreventing a long-continued over-charge of the battery. It is, however,equally, or

even more, desirable that the battery should always be recharged to itsfull capacity, to compensate for the discharge and to maintain thebattery in condition to perform its intended functions whenever calledupon to do so. Indeed, it is desirable that the stor ge battery shouldalways be slightlyoverable, particularly in car-lighting systems in'which the energy is supphed from a generator driven from the car axle:Inisuch systems each car to be lighted is provided with a generator, aystorage battery, and some means for regulating or controllmg the outputof the generator at all the varylng speeds above the critical, that 1s,above the speed at which the generator output 1s sulfic1ent to warrantits connection 'to the storage battery.

There are a number of well known devices for so regulating the output ofsuch enerators, among which may be mentloned; c levices for regulatingthe, tension of the driving belt, so that the belt Wlll sl1p when theoutput exceeds a predetermlned l1m1t;

. devices for automatically varying the field current to compensate forthe speed variations; a compound reverse wlndmg on the field of thegenerator to compeiisate for such variation; and the use of a so-calledFbucker in connection with the generator to cause a variation in thefield current in inverse proportion tb the speed variation.

lhese various devices may be used to regulate the generator to {constantpotential, or to a constant current, according to their adjustment.These devices have served to take care of the variation of speed of thegeneretor in a satisfactory manner, but they all leave much to bedesired in the practical operation and handling of the system,particularly as regards the control of the storage battery, and thedetermination of its conditions of charge.

One of the greatest difficulties heretofore encountered in the practicaluse of storage batteries (where they are not continuouslyunder theimmediate supervision of experienced engineers who may keep accuraterecords of charge and discharge), is the difli culty of determining thecondition of charge of the battery. Among the methods employed fordetermining such conditions may be mentioned; the inspection of theelectrolyte and the plates, which cannot well be taken advantage of intrain-lighting systems, or in other systems where access to thebatteries is diflicult; the volt-meter test,

which owing to the variations in the internal condition of the batteryis not at all accurate and is practically worthless on open circuit; andthe hydrometer test, which necessitates a knowledge of the specificgravity of the electrolyte before charging, and a comparison of thatwith the specific gravity at the moment of observation. This lattercharge.

the tester, because of the possibility that new I electrolyte has beenadded to the battery by some other attendant; and the test is notaccurate because the condition of the specific gravity of theelectrolyte varies with the atmospheric conditions, which vary the. rateof evaporation of the electrolyte. It is, therefore, highly desirablethat some means should be provided for determining. at leastapproximately, the condition of charge of the battery at any time, whichmeans should be capable of easy observatlon and reading,-and shouldpreferably be automatically controlled, and may advantageously include apermanent record.

It is the object of my inventionto provlde a system of charging storagebatteries 11] which the batteries are automatically recharged to theirfullcapacit-y, regardless of the variations in the internal conditionsthereof, and the consequent variations in the potential of thegenerator, and yet one in which a long-continued over-charge of thebattery is automatically prevented.

It is a further specific object of the invention to provide an index,capable of being easily read, and which-is automatically actuated toshow approximately at least the condition of charge of the battery.

Furthermore, and particularly in connect1OI1 Wlt-h train-lightingsystems, there is frequently a liability to an over-discharge of thebattery which results in an injurious deposit upon,,or sulfatat-ion ofthe battery plates. It is a further object of my inventlon toautomatically prevent such over-dis- In the drawings I have illustratedthe best form of apparatus now known to me in which the invention may beembodied,

and for purposes of illustration I have shown this apparatus as used inconnection with the regulating apparatus for car-lighting systemsdisclosed in my prior Patents .Nos. 745,194, of November 24,1903; and

800,114, of September 19, 1905, though the I utility of the invention isin no wise limited to that particular regulating means, but, on thecontrary, any of the other known regulating means above mentioned, ortheir equivalents, may be used.

In the drawings, Figure 1 is a front elevation of the indicating,recording and controlling means. Fig. 2 is a top plan view thereof- Fig.3 is a section on line 8-3 of Fig. 1. Fig. 4 is a section on a line 4-4of Fig. 1. Fig. 5 is a detail of one of the controlling magnets of thedevice. Fig. 6 is an end elevation of. the apparatus shown in Fig. 1,looking toward the right.

Fig. 7 is a fragmentary section on the line 7-7 of Fig. 6. Fig. 8 is anend elevation the drawings, this of the other end of'the apparatus shownin Fig. 1, parts being removed to add to the clearness of illustration,and showing the connection of the device to the regulator of n earlierpatents, and Fig. 9' is a diagram or the circuit connections.

The gear wheel 1 is mounted to rotate loosely on the shaft 2 and,isdriven through the pinion 3 (see Fig. 8) from any suitable source. Inthe particular instance shown in pinion is niounted'on the cam shaft ofthe regulator of my earlier patents above-mentioned, and is arranged tobe driven continuously by the regular amotor whenever the lampsareturned on or whenever the generator has attained sufficient speed to beconnected to the feeding circuit.

' That is to say, this motor-operates whenmagn ever the generator issupplying current either to the battery or to the lamps, andwhen everthe battery is supplying current to the lamps, whether the generator isrunning or not. It will be understood, of course," that any otherdriving source may be utilized, provided that it is either continuouslydriv-. ing the pinion, or is always driving it when the generator isfeeding current to the bat-. tery or to the lamps, and also when thebattery is feeding current to the lamps, whether the generator isrunningor not. Splined to the shaft 2 is a second gear Wheel 4 about which arearranged the magnets 5, 6,7 8 and9, which control the position of'thestar wheels 10, 11, 12, 13 and 14, to each of which is connected apinion. The pinions of the star-wheels 10, 11, 12 and 13 are so placedthat they will mesh with the gear wheel 4 when the magnets'areexcited,but when the magnets are not excited the pinions are held out of mesh bysuitable springs. The pinion of the star-wheel 14 meshes with an idler15 when the magnet 9 is excited, and is held out of mesh by a suitablespring when that magnet is not excited. Upon the face of the gear wheel1 are three pins 16, adapted to strike and turn the star-wheel 14 whenthe et 9 is excited, thereby driving the gear wheel 4 and the shaft 2 inone direction. The face of the gear wheel 1 also carries asingle pin 17which is longer than the pins .16 and is adapted to strike and turn anyone of the star-wheels 10, 1 1, 12 or 13 whichhas been brought by itsmagnet into such a position that its pinion gears with the wheel 4, tothereby turn the gear wheel in a reverse direction. On the shaft 2 is aworm 18 and at each-end thereof a loose collar 19 pressed against theend of the worm by the spring 20. Traveling on the worm is a pointer 21,the upper end of which serves to indicate on the scale 22 the number ofhours during which the battery has been charged, and the lower endofwhich carries a projection 23 adapted to close in turn the snap switchesH, G and F as the pointer moves from left ,65 to right, or to open thoseswitches in turn as the pointer moves from right to left. On

the otherend of the'shaft 2 outside of the supporting frame-work isloosely mounted a sleeve 27 carrying a ratchet 28 which has a pawl 29supported from the supporting frame and arranged toprevent a turningofthe ratchet 28 in a counter-clockwise direction as viewed in Fig. 6.Fixed to the extreme end of the shaft 2 is an arm 30 carrying a secondpawl 31 arranged to slide over the ratchet in a counterclockwisedirection as viewed in Fig. 6, and to turn the ratchet in a clockwisedirection as viewed in that figure. arranged to strike the star-wheel 33mounted for rotation on a stub shaft supported on the frame. This stubshaft carries a pinion 34 which meshes with the gear 35 on the end ofthe shaft 36 of the main paper reel 37 which is arranged in conjunctionwith a reserve paper reel 38 mounted in suitable bear-v ings 39 in theframe. The mechanical operation of these parts is as follows: Unless themagnets 5, 6, 7, '8 and 9,*or some of them,

are excited, the gear wheel 1 rotates freely without affecting theindicating mechanism. As soon, however, as any one of those magnets isexcited the corresponding pinion is brought into mesh and the,corresponding star-wheel is actuated by the" pins 16 or 17, as the casemay be, to turn'the gear 4 and the shaft 2. The star wheel of magnet 9causes rotation in a direction to move the pointer 21 to the right toindicate a charge, and the star wheels of magnets 5, 6, 7 and 8 cause arotation in the other direction to move the pointer to the left toindicate a discharge. Mounted on the pointer by a flexible support 40 isrotates in a direction to indicate a charge the paper reel 37 is notrotated and the record line is straight, but when the rotation is in adirection to indicate a discharge the ratchet 28 is rotated to rotatethe paper reel 11% and the recordline is correspondingly altered. v

The regulating device of my earlier pat ents in connection with which mypresent invention is illustrated, is one in which the regulation iseffected by inserting resistance in the field magnet circuit of thegenerator to reduce its current output. This insertion of resistance isefiected by the mechanism illustrated in a fragmentary way in Fig. 8 ofthe drawing, in which the rheostat arm 43 controls the resistance of thefield magnet circuit of the generator. The rheostat arm is controlled bythe magnet 44, Y which carries a' main winding S in series with thegenerator, a series of individual coils B, C, D and E'- which are inshunt to the individual lamp switches and are On the face of pinion 28is a pin 32 80 a stylus 41. When the shaft 2 105 wound in such adirection as to oppose the eflect of the series coils S, and a co 1l Fwhich is in shunt to the generator circuit, is wound in a direction toassist the effect of the series coil S, but does not become effective,until the battery is fully charged, as will be further explained. Thearmature 45 of the magnet is carried by the lever 46 which is pivoted toa stationary support at 42. When the lever is in the normal position(seen in Fig. 8), the cam 47, whlch is on the shaft of the motor abovementioned, rotates between two rollers 48 on the lever 46 withoutactuating the lever sufliciently to cause the pawls 49 and 50 to engagethe ratchets 51 and 52, which are reversely arranged and attached to therheostat arm 43.

The attraction of the magnet is opposed bythe two springs 53, and underthe normal conditions the effect of the springs balanced by the pullofthe magnet to maintain the parts in the inactive position shown, so thatalthough the cam is rotating between the Wheels 48 it does not move therheostat arm. If the magnet is weakened, the armature is depressed,turning the lever 46 on its pivot and lifting its outer end carrying thepawls 49 and 50. When this occurs the pawl 50 pressed by spring 62 isbrought into engagement with the ratchet 52, and thereupon the rockingof the lever turns the rheostat arm in a direction to cut resistance outof the field magnet circuit. If the magnet 44 is strengthened, thearmature is attracted and the pivoted pawl 49 becomes effective to cutresistance into the field magnet circuit."

Referring again to Fig. 1, it will be observed that the switches F, G,and H are snap switches of similar construction, and a detaileddescription of one will sufiice for allof them. Thus referring to theswitch F, the spring contact plate 54 and the bent piece 55 constitutethe terminals of the circuit. The spring plate 54 is mounted on asuitable standard provided with an ordinary binding screw and the piece55 is carried by the movable arm 56 of the switch, which is pivoted inthe standards 57 and provided with the latch spring 58 to hold it in setpositions. The actuating'member of the switch is the striker 59, whichis pivoted in the upper portions of the standards 57 and has an extendedfinger 60 to which is connected the spring 61, the other end of which isconnected to a fixed support. As the projection 23' on the pointer 21moves to the right, it turns the striker 59-on its pivot until thefinger 60 has engaged the turned over port-ion of the arm 56, and liftedthe piece55 to such an extent that the spring 61 begins to act above thepivotal center --of the striker 59, whereupon the switch snaps into thecircuit-closing position. The circuit-opening action is the reverse ofthat just described and will readily be understood. g

Having thus described the eration of the separate parts employed, we arein a position, upon referring to the diagram of circuit connections(Fig. 9), to

understand the operation of the charging system as a whole, assumingthat the battery is entirely discharged, and the gener-' ator is atrest, in which case all of the parts will be in-the ositions shown inthe drawings', with all of the magnets 5, 6, 7, 8 and 9 inert so thattheir respective star wheels and pinions will be inefiective. Uponstarting the generator no current flows in the,

main charging circuit until the automatic,

switch SW is closed. This switch isarranged to close automatically whenthe generated electromotive force 7, has risen sufficiently to warrantthe connection of the generator to the charging circuit. This may beaccomplished in various ways, well known to electrical engineers, as,for example, in the manner described in my earlier patents abovementioned. Upon the closing of this switch current will flow from thepositive terminal of the generator through circuit a, through the seriescoil S on the magnet 44, through the battery to charge it, and back tothe negative terminal of the generator, all the other circuits beingopen, as shown.

The capacity of the generator is so chosen that as the train, or otherdriving power, speeds up, current in the coil S almost immediately risessufliciently to cause magnet 44 to begin to cut resistance into thefield circuit of the generator. As soon as this movement has started,switch is released by rheostat arm 43 and allowed to close, whereuponcurrent flows from the generator through circuit 6 and magnet 9,exciting that magnet and bringing its star wheel and pinion intooperative position. Whereupon the rotation of the gear Wheel 1, as abovedescribed, begins to turn worm 18 in a direction to move pointer 21 withits projection 23' to the right. lVhen' this charging of the battery hasbeen continued long enough to establish in the battery a suitable,minimum charge, switch H is closed by projection 23, thereby'clcsingcircuit 0 containing the magnet of switch H and constituti'ng a shunt onthe cuit from the hand switch HS, which ordinarily remains closed, to apoint on the negative side of the battery. The current flowing throughthis shunt .clo-ses switch H to supply current .to the emergency bank oflamps 55 through circuit 03 and hand switch 56 which should alsoordinarily be closed. The closing of this circuit also allows current toflow through shunt circuit e to magmechanical op- A (see Fig. 8)

net 8, and through coil Bon magnet 44. This brings star wheel 13 and itspinion into operative position, causin a reverse rotation of the worm 18to in icate a discharge. It also weakens magnet 44 and causes it tocutout resistance from thefield magnet. circuit of the generator,thereby increasing the flow of current from the generator.

.For practical purposes I have found it advantageous to so adjust thearts that the.

amount of resistance out out mm the field magnet circuit will allow anincrease of the current flow e ual to about one-third of the currenttakenv y the-lamps. For example, the storage battery may ordinarily besupplied, when all the lamps are cut out, with a current of about thirtyamperes. If then we suppose that the emergency bank of lamps takes tenam eres, the adjusting will be such that enougi resistance will be cutout of the field magnet circuit to increase the current flow to 33%amperes, of which ten amperes will flow to the lamps and 23;); to thebattery. It will be observed, however, that whereas worm 18-, in thiscondition of the parts continues to be given three advance turns bystarwheel 14, it will'be given but one. reverse turn by star wheel 13,so that its indication of charge is two thirds of what it was before,which in"this particular example equals 20 amperes, whereas, as amattefof fact, the actual charge ,to the batteries-'-twenty-three andone-third am eresis' somewhat in excess ,of two thirds o the normalcharge of 30 amperes. It would, of course, be possible to so adjust theparts that the advance of the worm would be correspondingl in excess oftwo thirds of what it was bef ore', but it is preferable to adjust theparts in the manner indicated so that the actual charge is slightly inexcess of that indicated. In other .words, the reverse movement .of thepointer, is slightly diminished so that the battery will actually becharged to a slightly greater amount or for a longer period of timefigured on a thirty ampere-hour basis than that indicated. This courseis adopted for the following reasons: (a) It is primarily intended thatthe pointer 21 should indicate approximately the number of ampere-hoursavailable in the battery for lighting the-lamps. The numbers on thescale indicate the hours figured on a basis of, say,

thirty amperes, or whatever convenient number is adopted. It is a fact,however, that the output capacity of a battery falls below the energywhich has been expended in charging it by a percentage which is fairlyconstant and ranges around twelve per cent. One object then ofindicating less than the actual ampere-hours of charge is to make up forthis loss; (6) it is also true ipiaassature, eta, and there is a certainloss in the battery from leakage; etcl, all -of which things tend todiminish theefi'ective charge below what it would be under theoreticallyperfect conditions. Moreover, a' slight overcharge of the battery, or anindication of slightly less charge than the battery actually contains,is tobep'referred to an under-charge or excessive indication, underpracticalconditions. Another object, then, of indicating less than theactual amperehours of charge is to allow for these variations and insurethat the battery shall certainly be capable of giving the indicatedoutput; and rat-her more than less.

A further effect of the action thus far described is that the reversemovement of the worm 18 will have turned the pinion 28 and thereby thepaper roll 37, so that a diagonal line on the record strip will indicatehow long and to what extent the lamps have burned. As the pointer movesfarther to the right it will close the switch G, preferably when thebattery has been charged to about half its capacity. This allows acurrent to flow through the, circuit f and the magnet of switch G,thereby closing that switch and putting the banks of lamps 57 58 and 59in condition to have their circuits closed-through the circuit 03, whenthe hand switches 60, 61 and 62'are closed, to light their respectivebanks of lamps. When these switches are closed the circuits e, e and eare completed through the respective magnets 7 ,6 and 5.to brin theirstar wheels 12, 11 and 10 with their'pmions into operative position, andto close the circuits of coils G, D and E on the magnet 44. The

effect in each caseis the same'as the effect of closing the circuit 6,so that when the lamps 57 are lighted the worm 18 is given two re versesteps to three advance steps; when the additional lamps 58 are lighted,the worm is given three reverse steps to three advance steps; and whenall of the lamps are lighted the worm is given fourreverse steps tothree advance steps. It will be understood that the lamps may be dividedinto any desired number of banks, with a corresponding number ofcontrolled magnets and coils on the magnet 4-4, four being shown heremerely as lndicating a satisfactory practical application. It will alsobe understood thatin each case the battery is really receiving somewhatmore current than is indicated by the pointer, for the reasons above setforth. If the train slows down sufiiciently to open the automatic switchSW, or if' for any other reason the generator ceases to supply currentto the charging circuit, and if then any or .all of the lamps continuein use, the

number of hours which it is desired to charge the battery, say, tenhours, the 10 switch F will be closed by projection 23 and thiswillclose circuit 6, containing the magnet of switch F. This circuit 6is in shunt to the charging circuit, so that the current carried by itis-proportional to the voltage on that circuit. It results from this,that after the battery charge has continued for.

the maximum number of-hours desired, the closure of switch F will act toclose switch F provided the voltage on the charging circuit is up to thepoint at which magnet F is set to operate; this magnet being'de signed.to operate when the voltage has reached a point which indicates a fullcharge on the battery, so far as exact indication in that way ispossible. If the voltage has not reached that point, the charging of thebattery will continue, and the hub of pointer 21' Will be run off of theworm 18, advancing collar 19 and compressing spring 20, whereupon acontinued turning of worm 18 will not further advance the pointer. If,however, the voltage on the charging circuit has reached thepredetermined point when the switch F is closed by projection 23, orwhenever after' switch F is closed the voltage reaches that point,switch F will close, thereby closing circuit 9 and exciting coil Fwhich, as before described, is wound in a direction to strengthen magnet44, and will, therefore, act to cut resistance into the field magnetcircuit of the generator, and cut down the current flow, preferably to apoint where a small maintaining current of two to four amperes flowsinto the'batteries, to make up for leakage and the like. If now. thedischarge of the battery begins again the hub of pointer 21 will beforced on to worm 18 by spring 20, to continue its indications. v

If, the discharge continues long enough pointer 21 will be moved backuntil, when there is only an indicated charge of aboutfive hours in thebattery, switch G will be opened automatically, thereby. cutting out'the banks of lamps controlled by that switch, and compelling aconservation of the remaining charge in the battery by limiting its useto the emergency bank of lamps. Upon a further reduction of the batterycharge to a point where only the desired minimum charge remains in thebattery an indicated charge of about 1.8 hours on the 30 ampere basishas been established in practice as a satisfactory point the switch Hwill be opened automatically to cut out the emergency bank of lamps,thereby absolutely preventing an over-discharge of the battery. k

worm 18, and the attendants would have to be relied upon to prevent anover-discharge.

It will be seen, then, that my system provides for,s o regulating theoutput of the generator that it 'will charge the battery undereonstantcurrent conditions, regardless of the electro-motive force ofthe battery (including in that term its internal resistance drop) for apredetermined time period; and that after that predetermined period ofcharge has elapsed the charging circuit to the battery will beautomatically opened if, or when, the voltage of the charging circuithas reached a predetermined point. This prevents an excessiveoverchargeg-and at the same time insures that the battery shall alwaysbe fully recharged. The system may also provide for automaticallyopening the battery circuit when its charge has fallen to apredetermined point, to thereby prevent an over-discharge; and morespecifically it may provide for conserving'the charge of the batterywhen it has fallen below a certain point by automatically cutting outall of.the lamps except those on the emergency bank.

The instrumentalities above described also provide an easily readindicator which always shows approximately the number of ampere-hours ofcharge in the battery and may indeed be made to show that exactly,

though I prefer, for the reasons stated, to so arrange the parts thatthe indication will always be slightly less than the actual charge. Thedevices furthermore provide a permanent record of the battery charge andthe discharge to the lamps. As I have already pointed out, the switch Fis preferably effective to cut down the current flowing to the batteryto such an extent as to allow only a small maintaining current to flow,to make up for the current losses in the battery. The purpose of thismaintaining current is to make up for losses in the battery, and theamount which is permitted to flow may vary from zero to a current ofsubstantial value, depending upon the conditions of operatio Thequestion of just how much current shall be allowed to continue to flowis one which may be left to the judgment of the engineer, though, I havereferred a maintaining current of two to ve amperes under ordinaryconditions. In any event, the difference between the charging currentand i the maintaining current is actually a difthe charging current isdiscontinued, I mean to distinguish it from the maintaining current andto include within the scope of the claims the cutting down of thecurrent to such an extent as to discontinue the charging current, andavoid the evils result-ing from an overcharge whether any maintainingcurrent continues to flow to the battery or not.

What I claim is 1. The method of charging storage batteries whichconsists in supplying a charging current to the storage battery for apredetermined number of ampere hours regardless of the electromotiveforce of the battery, and thereafter causing a predetermined maximumpotential difference across the battery terminals to discontinue thecharging current, substantially as described.

2. The method of chargin storage batteries, which consists in supp yinga charging current of substantially constant value to the storagebattery for a predetermined number of ampere hours regardless of theelectromotive force' of the battery, and

thereafter causing a predetermined maximum potential difference acrossthe battery terminals to disconinue the charging-current, substantiallyas described.

I driven from the car axle, a storage battery connected to saidgenerator to be charged. thereby, and mechanism for regulating thegenerator to a constant-current output, in

combination with a controlling device in said circuit which discontinuesthe charging current when the potential thereof reaches a predeterminedlimit, and mechanism for rendering the controlling device inoperativeuntil the battery has been charged to a predetermined number ofampere-hours: substantially as described. y

4. In a train-lighting system, a generator driven from the car axle, astorage battery connected to said generator to be charged thereby, andmechanism for regulating the generator to a constant-current output, in

-combination with a movable indicator for showing the number ofampere-hours to which the battery has been charged, a controlling devicein the charging circuit adapted to discontinue'the charging current whenthe potential thereof reaches a predetermined limit, and mechanism forrendering 5. In a train-lighting system, a generator driven from the caraxle, a storage battery.

connected to said generator to be charged thereby, and mechanism forregulating the generator to a constant-current output, in combinationwith a movable indicator for which the battery has been charged, acontrollin device in the charging circuit adapted to iscontinue thecharging chrrent when the potential thereof reaches a predeterminedlimit, mechanism for rendering the controllin device inoperative whichis actuated to a low the controlling device to operate when the movableindicator reaches a predetermined position; and a" device for making apermanent record associated with the indicator; substantially asdescribed.

6. In a device for indicating the charge supplied to a storage battery,a worm, an indicator driven thereby, a gear wheel attached to saidworm'for driving it, a series of electro-magnets arranged about the gearwheel, a star wheel and pinion connected to I the armature of eachelectro-magnet in such a position thatrwhen the magnet is excited thepinion is brought into mesh with the gear wheel, a series of lampsdivided into banks, connections for supplying current from each of saidbanks to one of said elec tro-magnets when the lamps in that bank areburning, an additional magnet in proximity to the sa1d gear wheel, astar wheel and pinion connected to the armature of said mag- .75 showingthe number of ampere-hours to 3 net, a gear meshed with said gear-wheel,and

adapted, when said additional magnet is excited, to mesh also with the1ast-named pinion, connect-ions for supplying current to said additionalmagnet whenever the batteries are receiving current, and mechanism forintermittently striking each of the star wheels which is in suchposition that its pinion meshes with the gear wheel, whereby the worm isrotated in one direction to indicate the charge and in the otherdirection to indicate the discharge; substantially as described.

7. In a train lighting system, a generator driven from the car axle, astorage battery connected to said generator to be charged thereby, atraveler, mechanism responsive to the current flowing in the batterycircuit to move the traveler a distance proportional to the charge inthe battery, a circuit-controlling device actuated by said traveler whenit r aches a predetermined position, a second circuit-controlling deviceresponsive to the difference of potential across the battery terminals,and mechanism for discontinuing '14 and pinion carried by the armatureof the flow of charging current to the battery when saidcircuit-controlling devices are both c1osed,.-substantially asdescribed.

8. In a system-forcharging storage batteries, a generator, a supplycircuitext-ending therefrom, a storage battery and translating devicescbnnected across said circuit in combination with mechanism forcontrolling the battery charge comprising a ing devices, substantiallyas described.

9. An indicating device for use in connection with systems for chargingstorage batteries, comprising a worm 18, a pointer 21 driven thereby, agear wheel 4 secured to the shaft of the worm, a series .of magnets.

arranged about said gear and adapted to be excited to indicate adischarge from the battery, a star wheel and pinion secured to thearmature of each magnet and adapted, when the magnet is excited to meshwith the gear wheel 4, an additional magnet 9 in proximity to the gearwheel and arran ed to be excited when the battery is being.

charged, a star wheel 14 and pinion carried by'the armature of saidmagnet, an idler pinion meshing with the said gear wheel, with which thepinion on the armature of the magnet 9--is adapted to mesh when thatmagnet is excited, a driven gear Wheel 1, a series of pins 16 arrangedto strike the star wheel 14.- when it is in the meshing position, and apin 17 arranged to strike the star wheels of the first mentioned seriesof magnets when they are in the mesh-' ing position,'whereby theindicator is moved in one direction to indicate a charge and in theother direction to indicate a dis charge; substantially as described.

10. In an indicating and controlling device for use in connection withsystems for charging storage batteries, a worm 1.8, a pointer 21 driventhereby, a gear,wheel 4 secured to the shaft of 'the worm, a series ofmagnets arranged about said gear and adapted to be excited to indicate adischarge from the battery, a star wheel and pinion secured to thearmature of each magnet and adapted, when the magnet is excited, to meshwith the gear wheel 4, an additional magnet 9 in proximity to the gearwheel and arranged to be excited when the battery is being charged, astar wheel said magnet, an idler pinion meshing with the said gear heel,with which the pinion .on the armature of the magnet 9 is adapted tomesh when that magnet is excited, a driven, gear wheel 1, a series ofpinslti arranged to strike the star wheel 14 when it is in meshingposition, and a pin 17 arranged to strike the star wheels of'the firstmen.- tioned series of magnets when they are in the meshing position,wherebythe indicator is moved in one direction to indicate a charge andin the other direction to indicate a discharge, and a switch Factuated'by the pointer when it reaches a predetermined position tocontrol'the charging circuit;'substantially as described.

11. An indicating device for use in connection with systems for chargingstorage batteries, comprising a worm 18, a pointer 21 driven thereby, agear wheel 4 secured to the shaft of the worm, a series of magnetsbattery, a star wheel and pinion secured to the armature of each' magnetand adapted, whenthe magnet is excited, to mesh with the gear wheel 4,an additional magnet 9 arranged about said gear and adapted to beexcited to indicate a discharge from the in proximity to the gear wheeland arranged to be excited whenthe battery is being charged, a starwheel 14 and pinion carried by the armature of said magnet, an idlerpinion meshing with the. said gear wheel, with which the pinion on thearmature of themagnet 9 is adapted to mesh when that magnet is excited,a driven gear Wheel 1, a series of pins 16 arran'ged to strike the starwheel 14'when it is in the meshing position, and a pin 17 arrangedtostrike the star wheels of the, first mentioned series of magnets whenthey are in the meshing position; whereby the indicator is moved in onedirection to indicate a charge and in the other direction to indicate adischarge, and a spring-pressed collar 20 at the end of the worm,whereby the pointer may run out of engagement with the worm and. bethereby brought to rest; substantially as described.

12. In a train lighting systemfa storage battery, lamps fed therefrom,and-mechanism for automatically-cutting out a portion of the lamps toconserve the battery charge when said charge falls below a p'redeter:

mined point, substantially as described.

13. In a train-lighting system, a generator driven from the car axle, astorage battery charged thereby, a movable indicator automaticallyactuated to show the amount of charge, an over-charge switch. F actuatedby the indicator when it reaches the. position indicating the maximumcharge desired, an under-charge switch I-I actuated by the indicatorwhen it reaches a position indicating the lowest point to which itisdesirable to discharge the battery, and an intermediate switch Gactuated by the indicator in an intermediate position; substan- 5 tiallyas described.

14. In a train lighting system, a storage battery, lamps fed therefrom,mechanism for automatically cutting out a portion of the lamps whenthebattery char e falls be- 10 low a predetermined point, w ereby thebattery charge is conserved, and mechanism of the lamps when the atterycharge falls below a predetermined lower point, whereby excesslvedischarge of the battery is pre vented, substantially as described.

In testimony whereof I afiix my signature, in presence of two witnesses.

PATRICK KENNEDY.

Witnesses:

AUG. TREADWELL, J r., WALTER E. GREEN.

